A drive power supply of an electrical vehicle (EV) and a hybrid electric vehicle (HEV and PHEV) requires a high capacity and a high output characteristic. Thus, each battery increases in size, and a large number of batteries are used by being connected to each other in series, in parallel, or in series-parallel. Prismatic secondary batteries are being widely used as the batteries in terms of space efficiency. The secondary prismatic batteries use a high-output battery in addition to an increased battery capacity. When a high output is discharged, a large current flows through a battery and thus, an internal resistance of the battery is needed to be lowered. For this reason, various improvements have been carried out with regard to realizing a reliability enhancement and a low resistance in a junction of a terminal member (a member passing through a sealing body) and an external conduction member (an external terminal board connected to the terminal member, a bus bar, and the like) to reduce an internal resistance of a battery as possible, and prevent a fluctuation of an internal resistance.
When only a mechanical caulking is merely used under an environment including a lot of vibrations of an EV, an HEV, a PHEV, and the like as a scheme of realizing a low resistance in the junction of the terminal member and the external conduction member of the batteries, there is a concern that an electric resistance changes over time. For this reason, as disclosed in JP 2010-033766 A, a boundary of the junction by caulking of the terminal member and the external conduction member is welded by a high energy ray such as a laser.